Displays such as CRT and LCD are used as data display user interfaces or data input/output user interfaces for PCs, communications terminals and various information appliances. For such displays, a screen image, for which functions that suit the usage of an information appliance are set, is displayed, for example, as a graphical user interface (GUI). Various functions, such as the arrangement of input buttons, settings for data input fields, processes to be carried out when the buttons are pressed, for example, are set for the GUI. As a programming language for developing application programs for setting the design and functions of such user interface screens, Java, which is distributed by Sun Microsystems, Inc., is used widely.
A program written in Java is converted into byte code as a computer/platform-independent Java executable file format, read by a Java virtual machine (Java VM) and converted (interpreted) into machine language and run on various apparatuses.
In Java, in order to create application software easily in a short period of time, software components that do not require re-compiling are prepared in advance, and programs are created by combining those components. In Java, a technology for making these components reusable (Java Beans) is constructed.
Components are set in units of various components such as, for example, windows to be displayed on a display, buttons, lists, combo boxes, text input fields and the like. For these components, there are defined “property” as attribute information such as, for example, shapes of buttons, position information and the like, “method” as a process as the result of an action for a component, and further “event” as a function for, when an action with respect to a component, such as the arrival of data, the occurrence of an interruption, the alteration of properties, the calling of a method or the like, occurs, communicating the event to another component. These “properties,” “methods” and “events” are taken to be elements of components in Java Beans.
The smallest executable program unit in Java is referred to as “class” and a Java Program is constituted by one or more classes. A class has a variable as data and a method as an action. It is possible to forward and store this program component that is set as a class to a PC or an information appliance through a network such as the Internet or a LAN, and on the side of the apparatus in which the class file is stored, a platform-independent Java virtual machine is able to run the program saved in the class file.
As described above, the various components that constitutes a GUI, such as buttons, lists, combo boxes, text input fields and the like, are set as components that have attribute information such as their shapes, position information and the like, and further, for which functional information such as methods, events and the like are defined.
In other words, the logical part that defines functions like, for example, the process to be carried out when turned on, the process to be carried out when turned off or the like, of a component (GUI component), such as a button or the like, that is set on a graphical user interface, and the display image of the component, that is, the graphics representation part, are integrated. In the programming process for designing a GUI, various applications are designed by selecting and setting components in which the logical part and the graphics representation part are integrated.
However, the most appropriate graphical image differs depending on the device that is to be equipped with the GUI. For example, the image may on the whole be made softer and more subdued, or the image may be such that functionality is prioritized and excessive graphics removed, and so forth. In creating GUIs that have differing images as mentioned above, with the above-mentioned configuration in which components that have their logical part and graphics representation part integrated, it becomes necessary to generate distinct components that suit each image, the burden of creating components increases, and it leads to an increase in the number of components.